This paper describes the effect of doping boron atoms to the intrinsic (i‐) layer on the stability of metal/n‐i‐p/ITO amorphous silicon solar cells. The stability is improved as the amount of doped boron atoms increases. We have explained the improvement in cell performance and its stability by the counterdoping of phosphorus with boron on the basis of the photo‐induced change of the electrical properties of slightly doped a‐Si:H films and the decrease of gap state density.